Guide and scraper



1966 J. c. TRIPPLEHORN 3,282,345

GUIDE AND SCRAPER Filed March 9, A964 INVENTOR JAMES C.TRIPPLEHORN ATTORNEYS United States Patent 3,282,345 GUlDE AND SCRAPER James C. Tripplehorn, 1013 Mary Ellen St, Pampa, Tex. Filed Mar. 9, 1964, Ser. No. 350,168 13 Claims. (Cl. 166-476) This invention relates toimprovements in the structure of rod guides and/ or paraffin scrapers of the type intended to be mounted at spaced intervals along sucker rods while the latter are being reciprocated within a tubing string during the pumping of an oil well. More particularly, the invention relates to scrapers which are made of resilient deformable material and which are provided with novel structure for engaging the sucker rod and for frictionally preventing slipping of th'e scrapers on the rod when subjected to severe axial forces.

It is a major object of this invention to provide an opposed-slot scraper and guide in which the slot through the wall in one end portion of the scraper is not diametrically opposite with respect to the slot through the wall in the other end portion of the scraper, but wher'ein the slots are twisted out of mutually opposite alignment so as to make it more difficult for a radial blow to accidentally knock the scraper off of the sucker rod. In the case of prior art opposed-slot scrape-rs, it has been relatively easy to dislodge the scraper from the rod by striking a radial blow against one of the slots. Such a blow tended to entirely dislodge the scraper by driving the sucker rod through both of the slots simultaneously. Such a blow might occur, for instance, when introducing a length of sucker rod into the tubing, or when stacking a plurality of sucker rods when they are out of the tubing. An improved structure results from wrapping the scraper around the rod beyond the 180 degree point, and thereby providing a structure which is more difficult to dislodge accidentally because of the fact that a blow delivered in a radial direction against the scraper at one of its slots is not transmitted through the body of the scraper directly to the other slot, but is transmitted to a portion of the scraper at which no slot is located. This r'e'latively simple improvement in structure does not .add materially to the difficulty of applying a scraper using a suitable tool, but it does prevent accidental dislodgement of the scraper, especially while the rod to which the scraper is attached is outside of the tubing string.

Another object of the invention is to provide an improved opposed-slot scraper in which the width of each slot at the end thereof located nearest to the central transverse slot is widened 0r flared where it enters the transverse slot to help start the scraper onto the rod when it is being applied thereto.

It is another principal object of the invention to provide an opposed-slot scraper having a conical exterior shape at its upper portion which is especially effective :for the purpose of tightening the grip of the scraper at the upper bore whenever the scraper is pulled upwardly into a zone of dense parafiin. Particularly when the sucker rod is being pulled upwardly to remove it from the tubing string, there is a strong tendency to accumulate a quantity of parafiin above the scraper, which quantity increases as the scraper moves upwardly within the tubing. Sometimes the parafiin deposit becomes so tightly bailed inside the tubing that it tends to dislodge the scrapers from their selected positions on the rod. The present invention provides a scraper whose upper portion has an upward and inward taper which, upon encountering and penetrating into a ball of paraffin, experience-s radially-inwardly directed forces so that the body is wedged even more tightly against the sucker rod to increase its grip when it most needs it. Thus, the present novel structure provides an increasingly tight grip on the sucker rod under the very conditions which create the tendency toward axial displacement, with the result that this radial component of "force becomes a vital factor contributing to the: successful removal of the sucker rod from the tubing. It is of course, highly undersirable to have the scrapers longitudinally dislodged on the sucker rod, since such disllodgement may permit a plurality of scrapers to pile up against a tool joint and accumulate such a ball of paraffin on top of the scrapers as to prevent further upward motion when seeking to retrieve the rod.

Another object of the invention is to provide a scraper having the above-mentioned conical shape at its upper end, and having a plurality of narrow lugs at the extreme upper end serving as albuttments to prevent another scraper from being telescoped onto this conical surface if a scraper should be driven downwardly against the scraper below.

Another object of the invention is to provide a scraper and guide having an improved shape providing an improved flow of oil therepast, meaning reduced turbulanc'e.

It is another primary object of the present invention to provide an opposed-slot structure which, by virtue of its built-in resilience, exerts a powerful frictional grip on the rod to prevent axial slipping thereon.

The present invention contemplates an embodiment wherein the body is made of a plastic material having springlike qualities which provide the device with the aforementioned tight grip on the sucker rod, and the invention further contemplates another embodiment wherein the device comprises a similar plastic structure but including in addition thereto one or more spring metal clips designed to augment the grip of the resilient body on the rod.

It is a further very important object of the invention to provide an opposed-slot structure which is molded from a plastic which in the presence of high temperatures and corrosive fluids often found in oil wells exhibits excellent stability with respect to its mechanical dimensions. The plastic is an electrical insulator serving to prevent electrolysis, and in addition it has excellent acid and oil resistance properties. The range of plastics which exhibit satisfactory physical and chemical properties, and at the same time may be molded to the desired form, include the following:

Polyvinylidene chloride Polyamides; molding Itype (nylon) Polytetra-fluoro ethylene Polychloro-trifluoro ethylene Polymethyl alpha chloro-acrylate Polyester diallyl phthalate Poly acetal resin One of the properties exhibited by scrapers made of one of the above plastics includes the important characteristic that the very parafiin which the device according to the present invention is intended to scrape has very little tendency to stick to the plastic surfaces since these surfaces are very smooth and non-porous. This is one important and unobvious property which distinguishes the present plastic scrapers from prior art metal devices, the paraffin having a strong tendency to adhere to the metal scrapers in the same manner as it adheres to other metal objects located in the well, such as the tubing and the sucker rod.

Other objects and advantages of the invention will become apparent during the following discussion of the drawing, wherein:

FIG. 1 is a perspective view of one of the present rod guides and scrapers mounted on a sucker rod and located within a length of pump tubing, the tubing being shown cut away so as to make the guide visible;

FIG. 2 is a section view taken along line 2-2 in FIG. 1;

FIG. 3 is an elevation view of the guide and scraper shown in FIG. 1, but rotated to another viewing position in order to show the slot in the lower portion of the scraper;

FIG. 4 is a section view taken along line 44 of FIG. 3;

FIG. 5 is an elevation view of a guide and scraper similar to that shown in FIG. 3, but rotated to another viewing position in order to show the shape of the slot through the upper portion of the guide, the guide shown in FIG. 5 being also modified to illustrate the presence of spring-steel clips in the upper and lower bores for the purpose of tightening the grip of the guide and scraper on the sucker rod;

FIG. 6 is a section view taken along line 6-6 of FIG. 5, and

FIG. 7 is a perspective view of a spring clip of the type illustrated in the modification shown in FIGS. 5 and 6.

Referring now to the drawing, FIG. 1 shows a sucker rod R disposed within a length of pump tubing T, the latter being shown in cross-section so as to show a guide and scraper according to the present invention located in operative position within the tubing and gripping the sucker rod. The guide and scraper illustrated in FIG. 1 may, or may not, include spring clips of the type shown in FIG. 7 andintended to augment the grip on the sucker rod R. The scraper and guide itself includes a body 1 having an upper portion 1a and a lower portion 1b joined together by an intermediate portion located opposite a transverse slot 1d through the body. The body ll has a bore 2 which extends all the way through it and includes an upper bore 2a and a lower bore 2b.

The upper portion 1a of the body has a slot 3a through its side wall and communicating with the upper bore 2a; and the lower portion of the body 1b has a slot 3b extending through it and communicating with the bore 2b through the side wall of the body, and the slOts 3a and 3b are located approximately opposite each other, but offset by an angle 0 of about 10 to degrees, as can be seen in FIGS. 2, 4, and 6. The angle 9 provides a wraparound effect serving to discourage and prevent accidental dislodgement of the scraper from the sucker rod by a blow against one of the slots in an essentially radial direction.

The width of both of the slots 3a and 3b is graduated so that the slot is narrowest at its extreme outer end, but is widened as at and 3d so as to make it easier to start the sucker rod into the bores 2a and 2b from the transverse slot ltd.

Both the upper portion 1a and the lower portion 1b of the guide are streamlined and tapered so as to make it easier to draw them past obstructions and tool joints in the tubing string; and in addition, the outer surfaces of the upper portion Ia of the body 1 are essentially conical in shape as can be seen best in FIGS. 3 and 5. This conically shaped upper end is an important and novel feature during upward motion of the body can provide a wedge action so that when the guide is being raised within a length of tubing as shown in FIG. 1, if the guide encounter a ball of parafiin thereabove, this paraffin will provide an inward component of force on the conical outer surface le of the upper portion of the scraper, and thereby increase the grip of the upper portion of the scraper on the sucker rod by wedging it inwardly andmore tightly thereagainst. e 1 p In order to obtain a long tapered shape at the upper portion at 12, it is necessary to taper the upper portion down to a relatively small upper end. However, because of the small diameter at the extreme upper end, there is danger that this scraper might tend to telescope into another scraper located thereabove and expand it outwardly into wedging contact with the tubing wall.

This condition might occur particularly where a combination of alternating fixed and ambulatory scrapers is used, for instance, as shown in my Patent 2,997,106. I have therefore provided plural narrow lugs 4, 5, and 6 serving as abutmen'ts to prevent such telescoping of the scrapers, without substantially affecting the wedge characteristics of the conical wedging surface 1e.

FIGS. 5, 6, and 7 are directed to a modification of the guide and scraper to provide means for increasing the grip of the device upon the sucker rod. It is, of course, desirable to provide a scraper in which there are no metal parts so as to enjoy the benefit of the non-corrosive nature of the plastic material. However, in some wells exhibiting extreme ambient conditions, for instance of heat, it may be necessary or desirable to provide a steel cli-p within the plastic body to insure an unyielding grip on the sucker rod. This may also be the case where a rubber or plastic material having less of a natural grip, for instance than nylon, is used as the material of which the body I is made. A steel clip 10, as shown in FIG. 7 can be inserted into the mold at the same time the scraper is being molded and positioned so as to lie flush with the bore in the finished product, the clip being C- shaped and positioned within the mold so that the opening of the clip coincides with the position of the slot opposite which it is to be placed. In this way, when the plastic material is molded around the clip, it will remain within a recess in the bore 2 of the body. The spring clip is thus retained in the recess which is formed in the body at the time the latter was molded. Although FIG. 5 shows clips in both the upper and lower bores, it is to be understood that the clip may be used in only one of the bores if desired. As shown in FIG. 6, the clip appears to be embedded in the plastic, rather than lying on the surface of the bore 2. Thus, depending on the type of plastic used, the manufacturer may decide either to have the clip 10 exposed to fluids within the well because it is merely recessed into the surface of the bore, or else the clip may actually be embedded in the plastic itself so as to protect it against corrosive contact with the well fiuids. The latter situation would be desirable, for instance, in a case where the body 1 is made of rubber, and the steelspring clip can be successfully bonded to the .rubber within the body. The number, and the axial lengths of such clips, and their positions may be selected and varied to suit particular circumstances. 1

In operation, when it is desired to attach the scraper and guide shown in the drawing to the appropriate ize of sucker rod, the body is tiltedso that its axis is disposed transversely with respect to the axis of the sucker rod, and the sucker rod is then passed into the transverse slot 1d of the scraper and guide. Next, the latter is tilted back again so that its axis approaches the axis of the sucker rod and so that the sucker rod extends into the axially disposed slots 3a and 3b. Then, the scraper and guide is given either an additional blow or is pressed, as by a hydraulic press, until the sucker rod is snapped into the bore 2 extending toward both ends of the scraper and guide from the center thereof. Because of the narrowness of the slots 3a and 317, it requires a great deal of force to pass the sucker rod into the bore by flexing the body open at each slot, but once positioned in the bore, the sucker rod is very tightly gripped by the device. Depending upon the magnitudes of the expected axial forces tending to move the device along the sucker rod either the form without supplementary steep clips as shown in FIG. 3 may be used, or else in the case of anticipated severe stresses, the scraper and guide, according to FIG. 5 may be employed. It is extremely important that, once positioned on the sucker rod R, the device holds thereto tightly enough to maintain its installed position.

Working models of both forms of the device have been made out of nylon, and have proven very successful when used in oil pumping operations in relatively deep wells. Nylon is extremely hard and has a grip of its own on the sucker rod which is quite similar to the grip of a spring clip.

The scope of the present invention is not to be limited by the exact forms shown in the drawing, for obviously changes may be made therein within the scope of the following claims.

I claim:

1. In oil well equipment, a guide and scraper to be attached to a sucker rod, said guide and scraper comprising an elongated body of resilient deformable material with a longitudinal bore therethrough to receive the rod, the diameter of the bore being slightly less than the diameter of the rod, the body having a slot through its side disposed transversely of the bore and extending to the full depth thereof and wider than the diameter of the bore, and said body having two longitudinal slots therethrough communicating with said bore and narrower in width than the diameter thereof, and these two slots extending from opposite ends of the transverse slot to opposite ends of the body, the transverse slot being located near the longitudinal center of the body and the exterior contour of said 'body tapering down substantially continuously from the transverse slot to about half its central diameter adjacent at least one end of the body to provide an elongated generally frustoconical surface.

2. In a guide and scraper as set forth in claim 1, plural narrow a'butments extending radially outwardly from said frustoconical surface at said one end of the body.

3. In oil well equipment, a guide and scraper to be attached to a sucker rod, said guide and scraper comprising an elongated body of resilient deformable material with a longitudinal bore therethrough to receive the rod, the diameter of the bore being slightly less than the diam eter of the rod, the body having a slot through its side disposed transversely of the bore and extending to the full depth thereof and wider than the diameter of the bore, and said body having two longitudinal slots therethrough communicating with said bore and narrower in width than the diameter thereof, and these two slots extending from opposite ends of the transverse slot to 0pposite ends of the body, and the exterior contour of said body tapering down in diameter from the transverse slot toward at least one end of the body to provide at that end thereof a generally frustoconical surface, said two longitudinal slots being disposed on circumferentially opposed sides of the body with respect to the axis of the bore but the slots being offset from exactly opposite each other by an angle in the range of to 20 degrees.

4. In oil well equipment, a guide and scraper to be attached to a sucker rod, said guide and scraper comprising an elongated body of resilient deformable material with a longitudinal bore therethrough to receive the rod, the diameter of the bore being slightly less than the diameter of the rod, the body having a slot through its side disposed transversely of the bore and extending to the full depth thereof and wider than the diameter of the bore, and said body having two longitudinal slots therethrough communicating with said bore and narrower in width than the diameter thereof, and these two slots extending from opposite ends of the transverse slot to opposite ends of the body, and the exterior contour of said body tapering down in diameter from the transverse slot toward at least one end of the body to provide at that end thereof a generally frustoconical surface, each of said two slots being flared for part of its length and thereby widened where it opens .into the transverse slot to a width greater than the diameter of said bore.

5. In a guide and scraper as set forth in claim 4, at least one C-shaped spring metal clip embedded in said body and surrounding a length of said bore and having an opening registering with the sides of one of said longitudinal slots.

6. The guide and scraper as set forth in claim 4 wherein said material is nylon.

7. In oil well equipment, a guide and scraper to be attached to a sucker rod, said guide and scraper comprising an elongated body of resilient deformable material with a longitudinal bore therethrough to receive the rod, the diameter of the bore being slightly less than the diameter of the rod, the body having a slot through its side disposed transversely of the bore and extending to the full depth thereof and wider than the diameter of the bore, and said body having two longitudinal slots therethrough communicating with said bore-and narrower in width than the diameter thereof, and these two slots extending from opposite ends of the transverse slot to opposite ends of the body and being disopsed on circumferentially opposed sides of the body with respect to the axis of the bore, but said slots being offset from exactly opposite each other by an angle in the range of 10 to 20 degrees.

8. In a guide and scraper as set forth in claim 7, each of said two slots being flared for part of its length and thereby widened where its opens into the transverse slot to a width greater than the diameter of said bore.

9. Ina guide and scraper as set forth in claim 7, at least one C-shaped spring metal clip embedded in said body and surrounding a length of said bore and having an opening registering with the sides of one of said longitudinal slots.

10. The guide and scraper as set forth in claim 7 wherein said material is nylon.

11. In oil well equipment, a guide and scraper comprising an elongated body of resilient deformable material with a longitudinal bore therethrough, the body having a slot through its side dividing the body into upper and lower portions, the slot being disposed transversely of the bore and extending to the full depth thereof and at least as wide as the diameter of the bore, and said body being greatest in diameter in the vicinity of the slot and having two longitudinal slots therethrough communicating with said bore and extending from opposite ends of the transverse slot to opposite ends of the body, the upper and lower portions of said body tapering down in diameter from the transverse slot toward the ends of the body to provide generally frustoconical contours, and said longitudinal slots being disopsed on circumferentially opposed sides of the body but offset from being exactly opposite each other by an angle in the range of 10 to 20 degrees.

12. In a guide and scraper as set forth in claim 11, each of said two slots being flared for part of its length and thereby widened where its opens into the transverse slot to a width greater than the diameter of said bore.

13. In a guide and scraper as set forth in claim 11, at least one C-shaped spring metal clip embedded in said body and surrounding a length of said bore and having an opening registering with the sides of one of said longitudinal slots.

References (Iited by the Examiner UNITED STATES PATENTS 2,436,994 3/1948 Gillespie 166176 2,928,472 3/1960 Tripplehorn l66l76 2,928,473 3/1960 Tripplehorn 166-176 3,083,772 4/1963 Tripplehorn 166-l76 3,186,773 6/1965 Harris et a1. 3084 JACOB L. NACKENOFF, Primary Examiner.

CHARLES E. OCONNELL, Examiner.

D. H. BROWN, Assistant Examiner. 

4. IN OIL WELL EQUIPMENT, A GUIDE AND SCRAPER TO BE ATTACHED TO A SUCKER ROD, SAID GUIDE AND SCRAPER COMPRISING AN ELONGATED BODY OF RESILIENT DEFORMABLE MATERIAL WITH A LONGITUDINAL BORE THERETHROUGH TO RECEIVE THE ROD, THE DIAMETER OF THE BORE BEING SLIGHTLY LESS THAN THE DIAMETER OF THE ROD, THE BODY HAVING A SLOT THROUGH ITS SIDE DISPOSED TRANSVERSELY OF THE BORE AND EXTENDING TO THE FULL DEPTH THEREOF AND WIDER THAN THE DIAMETER OF THE BORE, AND SAID BODY HAVING TWO LONGITUDINAL SLOTS THERETHROUGH COMMUNICATING WITH SAID BORE AND NARROWER IN WIDTH THAN THE DIAMETER THEREOF, AND THESE TWO SLOTS EXTENDING FROM OPPOSITE ENDS OF THE TRANSVERSE SLOT TO OPPOSITE ENDS OF THE BODY, AND THE EXTERIOR CONTOUR OF SAID BODY TAPERING DOWN IN DIAMETER FROM THE TRANSVERSE SLOT TOWARD AT LEAST ONE END OF THE BODY TO PROVIDE AT THAT END THEREOF A GENERALLY FRUSTOCONICAL SURFACE, EACH OF SAID TWO SLOTS BEING FLARED FOR PART OF ITS LENGTH AND THEREBY WIDENED WHERE IT OPENS INTO THE TRANSVERSE SLOT TO A WIDTH GREATER THAN THE DIAMETER OF SIDE BORE. 